Core oil



Patented Feb. 10, 1942 2,272,483 com; on.

Madison L. Sheely, Des Plaines, Ill., assignor to Armour and Company, Chicago, 111., a corporation of Illinois No Drawing. Application February 23, 1938,

Serial No. 192,075

17 Claims.

The present invention relates to an improved core oil for use as a binder for sand in the production of sand mold for cores and has for its principal object the provision of a core oil including a special fatty acid composition obtained from marine oils.

An additional object is to provide an improved core, the particles of which are bonded together by residual portions produced in the fractional distillation of marine oils and containing unsplit oil in admixture with unnatural quantities of high molecular weight unsaturated fatty acids.

Another object is the preparation of a core from sand and a special fraction of marine oils including at least 40 per cent of unsaturated fatty acids of the C22 type and not more than 70 per cent free fatty acids.

A further object is the production of cores from a core oil of the type described in which the special fatty acid composition has been reesterified at least in part.

tion of the oil is not volatile and when the mix ture of unsplit oil and fatty acids is heated and flashed into a fractionatlng column the triglycerides pass downwardly through the column to be recovered as bottoms.

In carrying out the fractional distillation procedure the reflux and draw-off factors of the process are controlled so as to separate from the vbottoms the major quantity of lower carbon The separation of the lower stituents of the oil or fatty acids together with A still further object of the invention is to produce cores from an oil of the type described in combination with a drying agent and an antioxidant.

Core oils of the type known heretofore generally have been produced from linseed oil, Perilla oil, Chinawood oil, or other drying oils. Generally the oil is used with a mineral oil thinner, natural resins and synthetic resins or other body-imparting substances likewise may be in-' cluded with the oil. The oil in use is mixed with sand which is formed into the desired shape and baked to produce a core or mold structure which 5 jected to a splitting operation in which the unsplit content of the oil is reduced to the order of 10 per cent or less of the original unsplit oil. The liberated glycerine is removed with the water used in effecting the hydrolysis of the fish oil, and the relatively small percentage of unsplit oil remains with the fatty acids. The unsplit porthe fatty acids of the C22 type and the residual unsplit glycerides. The triglycerides may contain in combined form acid radicals of lower molecular weight than the C22 acids, since the original oil contains many different fatty acid radicals apparently combined somewhat indiscriminately as triglycerides.

If the amount of unsplit triglycerides in the bottoms is so great that the quantity of C22 fatty acid radicals is below that desired for the product, the latter may be enriched by the addition of fractionated fatty acids of the C22 type. It is preferred that the added C22 acids be re-ester ified. The relative amounts of the special fraction of fatty acids and undistilled oil contained in the bottom product may vary considerably, depending upon the desired characteristics of the final core oil. The extent of the original split and the thoroughness of the fractionation process by which the specially active fraction of fatty acids is separated also are factors entering into the control of the relative quantities of neutral oil and fatty acid.

The improved core oil has a composition including at least 40 per cent C22 fatty acid radicals and not more than '70 per cent free fatty acids. To obtain this composition directly from hydrolyzed marine oil by fractional distillation, the oil is split so as to produce at least 90 per cent free fatty acids. After the separation oper- 'ation is completed the free fatty acids may be reconverted into triglycerides. It is preferred that the product have a saponification value of low temperature.

not more than 185. The product generally will have an iodine value of between 190 and 250, but since more or less polymerization may be intentionally permitted the iodine value may be below this range.

In use, the fractionally separated core oil is mixed with clean, fine sand, the ratio being about 1 to 60 by volume or about 1 per cent core oil based on the weight of the sand. If desirable, small quantities of diluents, such as mineral oil products, and material binders such as corn flour may be added to the mixture. The mixture of sand and core oil is rammed into core boxes for producing the desired shape and after removal from the box the core is baked in an oven at a temperature which may range from 350 F. to 500 F. The time of baking varies in accordance with the size of the core, the nature of the core oil, and the baking temperature. Cores produced with the improved oil of this invention are more readily baked than cores known heretofore. For example, the baking time required to produce a satisfactory core is decreased considerably and it further is possible to bake the core at a relatively The improved oil also has the characteristic of imparting increased tensile strength to the core. There is a noticeable decrease in the volume of volatile material evolved during the casting period. This is of importance in increasing the fine quality of the cast material Baking time at 395 F.

45 min. 60min.

Pounds per Pounds per square inch squarrinch 104 12[ Linseed oil Menheden special fraction acids. 147 251 Sardine special fraction acids 284 293 From these tests it will be seen that the core oils produced by fractionation of menhaden fatty acids and sardine fatty acids provide cores greater in tensile strength than the cores produced with linseed oil. Further tests show that the fractionated fish fatty acid fractions produce a stronger core with forty-five minutes baking than does the linseed oil with more than twice this time of baking. The reduction in baking time obtained. by the improved oil is a material factor in plant operation. Thus, to obtain a core having a tensile strength of 200 it is possible to use a sardine oil and bake the core for less than forty-five minutes.

As before stated, thecomposition of the core oil may vary. considerably, depending upon the particular control factors in the fractionating process. The'core oil is rich in unsaturated C22 acid radicals and these acids largely constitute the active ingredients of the oil. However, the residual unsplit oil obtained from the bottom of the fractionating tower also seems to add to the desirable characteristics of the core oil. In many cases it is beneficial to subject the core oil to reesterification to convert the C22 fatty acids into the corresponding triglyceride. Particularly is this true where the free fatty acid content is above 70 per cent. For example, in producing the improved core oil from sardine oil the bottom product of the fractional distillation may contain more than 40 per cent C22 fatty acids and a substantial quantity of C20 acids as well, the total being more than per cent free fatty acids. This excess acidity may be removed by esteriflcation to produce synthetic triglycerides. It is possible to increase the special characteristics of the core oil by the addition of other materials. These materials may include diluents such as the volatile hydrocarbons or it may include resins or the like. Various modifying agents will be used with this particular type of core oil in the same manner as has been used in core oils before.

In the addition of modifying agents to the core oil the special characteristics of the latter can be augmented by the use of anti-oxidants and driers. Thus, when cores of markedly different sizes are used it is desirable to retard the baking of the smaller cores in order to allow sufllcient time for the baking of the larger cores. By incorporating antioxidants and driers in the core oil the baking of the larger cores may be accelerated and at the same time the over-baking of the smaller cores may be prevented. As an antioxidant, diphenyl amine, when used in small quantities such as 0.25 per cent, has been found satisfactory. A suitable drier for use in this connection consists of cobalt resinate which may be added in quantities of about 0.25 per cent on a cobalt basis. The tensile strength of the core is improved by the addition of these materials to the core oil.

The complex fraction of fatty acid materials comprising the improved core oil is considerably different in chemical nature than natural oils. When in unnatural concentration, as in the present case, this special fraction has characteristics not possessed by the original oil which makes the material of particular utility as a core oil.

The process of producing the special fraction described herein may be changed in detail, and the composition of the material may vary to a considerable extent without departing from the scope of the invention as defined in the anpended claims.

I claim:

1. A core oil, comprising a marine oil fatty acid composition containing at least 40 per cent C22 fatty acid radicals in a concentration substantially greater than in a normal fatty acid mixture of hydrolyzed marine oil.

' 2. A core oil, comprising a marine oil fatty acid composition containing C22 fatty acids in a concentration substantially greater than in a normal fatty acid mixture Obtained from hydrolyzed marine oil, said fatty acids being in admixture with marine triglycerides.

3. A core oil, comprising a C22 marine oil fatty acid composition having a baking time substantially less than the baking time of linseed core oil.

4. A core oil, comprising a C22 marine oil fatty acid composition admixed with marine triglycerides and having a concentration sufficiently greater than the concentration of C22 fatty acid radicals in marine oil to provide a baking time substantially less than linseedcore oil.

5. A core oil, comprising a C22 marine oil fatty acid fraction having a saponification value of not more than 185, being highly unsaturated, and having a baking time substantially less than linseed oil.

6. A core oil, comprising a C22 unsaturated marine oil fatty acid fraction containing the in concentrated form and marine oil fatty acid triglycerides, said core oil having a saponification value of not more than 185, and a free fatty acid content of not more than 70 per cent.

8. A core oil, comprising a marine oil composition containing not more than 70 per cent fatty acids and having a content of C22 fatty acid radicals of at least 40 per cent.

9. A core oil, comprising a re-esterified marine oil composition containing at least 40 per cent C22 fatty acid radicals, said composition being present in said oil in material quantity.

10. A core oil, comprising a C22 marine oil fatty acid composition containing at least 40 per cent C22 fatty acid radicals and being admixed with an anti-oxidant and a. drier.

4 11. The process of producing cores, which comprises mixing sand with a core oil composed of a marine oil fatty acid composition containing at least 40 per cent C22 fatty acid radicals, forming the sand and oil into the desired shape, and baking the mixture.

12. The process of producing cores, which comprises mixing sand with a marine oil fatty acid composition containing C22 fatty acid radicals in a concentration substantially greater than in a normal fatty acid mixture obtained from hydrolyzed marine oil, forming the mixture into the desired shape, and baking the shaped mixture.

13. The process of producing cores, which comprises mixing sand with a C22 marine oil fatty acid composition having a faster baking time than linseed oil and being in admixture with a drier and an anti-oxidant, forming the resulting mixture into a plurality of shapes of different sizes, and subjecting the shaped mixtures to baking.

14. The process of producing cores, which comprises mixing core sand with a core oil containing at least per cent re-esterified-Czz marine oil fatty acids, forming the sand and oil into the desired shape, and baking the mixture.

15. The process of producing cores, which comprises mixing core sand with the bottom product of fractionally distilled incompletely hydrolyzed marine oil containing C22 unsaturated fatty acid radicals in concentrated form and marine oil triglycerides, forming the sand and bottom product into the desired shape, and baking the mixture.

16. A core, comprising a formed and baked mixture of core sand and a core oil composition containing at least 40 per cent C22 fatty acid radicals at least partially in the form of triglycerides.

17. As a new composition of matter a binding agent for sand cores consisting of re-esterified highly unsaturated fatty acids of fish oils, which fatty acids consist predominately of re-esterifled C22 fatty acid.

MADISON L. SHEELY. 

